The Role of Visual Attention and Environmental Complexity in Real-world Mobility for People With Lower Limb Amputation

20 participants with below knee amputation.

Assessment of accelerometry: Daily duration (minutes) of sitting, standing, stepping, Daily step count, Daily walking bouts stepping cadence, Timed Up and Go and Two-minute Walk Test

Comprehensive assessment of eye movements during walking including Target Fixation Time (seconds; %) and Number of fixations

The following assessments will be completed: World health organization disability assessment schedule 2.0 (WHODAS), and Activities Specific Balance Confidence Scale.

10 sex- and age-matched control participants.

Assessment of accelerometry: Daily duration (minutes) of sitting, standing, stepping, Daily step count, Daily walking bouts stepping cadence, Timed Up and Go and Two-minute Walk Test

Comprehensive assessment of eye movements during walking including Target Fixation Time (seconds; %) and Number of fixations

The following assessments will be completed: World health organization disability assessment schedule 2.0 (WHODAS), and Activities Specific Balance Confidence Scale.

Measure walking speed meters/second. Captured during dual-task and single-task walking, it is used to measure motor performance. Normal Speed: Healthy adults usually walk at 1.2 to 1.4 meters per second.Fall Risk: A speed below 1.0 meter per second shows a higher risk for falls.Frailty Warning: A speed below 0.6 to 0.8 meters per second suggests a high risk of functional decline or disability.

Measure the stride length in meters. stride length is the total distance covered during one full cycle of walking or running with the same foot. It measures the space from where one foot touches the ground to when that exact same foot touches the ground again.

Assess Stride length asymmetry is an imbalance where the distance covered by the right and left steps differs. Symmetry Index (SI): Compares spatial step metrics or temporal single-limb support times between limbs.Percentage difference: Calculated by contrasting mean left and right step values; values exceeding 10% typically indicate notable dysfunction.

Accuracy (percentage correct) of each cognitive task. This reflects cognitive performance and is measured in both dual-task and single-task conditions.

Measure Response time (milliseconds)

Two-minute Walk Test measures the total distance a person can walk on a flat, hard surface within two minutes. It evaluates functional mobility, submaximal endurance, and self-paced walking capacity in adults. Recorded to the nearest meter or foot using a measuring wheel, and lap count.

Timed Up and Go (TUG) test measures functional mobility, dynamic balance, and fall risk by timing how fast a person stands from a chair, walks 3 meters (10 feet), turns around, walks back, and sits down. Under 10-12 seconds: Normal, independent mobility with low fall risk.12-20 seconds: Moderate risk of falling or subtle mobility issues; requires further evaluation.Over 14-20 seconds: High risk for falls; often indicates difficulty moving outside alone or a need for assistive devices.

Target Fixation Time (seconds; %), The length of time the eye remains relatively still on a target to process detail, reflecting visual attention.

Number of fixations is a core metric measuring how many times a person's eyes pause and focus on a specific area or object. High Fixation Count: indicates frequent attention on an area or element. Low Fixation Count: Means an element was quickly passed over, easily understood, or ignored.

The Houghton Scale assesses a person's confidence and ability in using their prosthesis safely and effectively during everyday mobility tasks. The Houghton Scale is a self-administered, 4-item questionnaire used to assess the functional use of a prosthesis by individuals with lower-limb amputations.It measures how often a patient wears their prosthesis, the types of activities they perform with it, and their perceived stability in various outdoor environments. Total scores range from 0 to 12, with higher scores indicating greater prosthesis use and independence

PEQ - Mobility subscale is the The Prosthesis Evaluation Questionnaire - Mobility subscale, captures a person's self reported ability to move and perform daily activities while using their prosthesis. It uses a 5-point ordinal scale (0-4). 0: Not able or hardly able to 4: No problem or almost fully able. The total scale ranges from 0 to 48. A higher score indicates greater mobility.

WHODAS The World health organization disability assessment schedule 2.0 (WHODAS) evaluates how health conditions impact a person's functioning and participation across major life domains over the past 30 days. Items are rated on a 5-point Likert scale: None (0), Mild (1), Moderate (2), Severe (3), and Extreme or Cannot Do (4). While no universal "cut-off" exists, scores placing a patient in the top 10% of the population distribution-roughly >10 for the 12-item simple score or >41 for the 36-item version-likely indicate significant impairment.

Activities Specific Balance Confidence Scale is a self-report instrument used to measure an individual's confidence in maintaining balance while performing 16 various daily activities. Unlike performance-based tests, it captures the patient's perceived ability to avoid falling or becoming unsteady.Patients rate their confidence for each item on a scale from 0% (no confidence) to 100% (complete confidence). The higher the score,the higher the function and physical activity (range > 80% high function, 50% - 80% moderate function and < 50% low function.

Daily duration (minutes) of sitting, standing, and stepping reported as an aggregate mean.

Daily step count will be measured and reported as an aggregate mean.

Daily walking bouts stepping cadence will be reported as an aggregate mean